Patent document 1 discloses a switch which is configured to rotate a knob around a rotational shaft to turn on a switching element.
Patent Document 1: Japanese Patent Laid-Open No. 2014-120322 A
FIG. 8A to FIG. 8C are drawings explaining a switch 100 according to a conventional example.
FIG. 8A is an exploded perspective view illustrating the switch 100.
FIG. 8B and FIG. 8C are cross sectional views explaining an operation of the switch 100.
As illustrated in FIG. 8A to FIG. 8C, the switch 100 disclosed in Patent Document 1 is provided with a knob 102 which is operated by a user. The knob 102 is supported by a case 101 provided in the switch 100 to be capable of swinging around a rotational shaft X1.
The case 101 is attached to a polar board 110 having a printed circuit board 109, and in this attached state, the knob 102 supported by the case 101 is arranged to face the printed circuit board 109 in a direction of attaching the case 101 to the polar board 110.
On the printed circuit board 109, a pair of switching elements 107, 108 are provided to be spaced from each other in a direction of the rotational shaft X1.
In the case 101, a pair of cams 105, 106 corresponding to the switching elements 107, 108 on a one-to-one basis are supported to be capable of swinging around a rotational shaft X2 in parallel with the rotational shaft X1.
The knob 102 is provided with a pair of operable elements 103, 104 on a facing portion to the printed circuit board 109, and engaging portions 103a, 104a provided in tips of the operable elements 103, 104 are engaged to engaging grooves 105a, 106a of the cams 105, 106 corresponding to the engaging portions 103a, 104a respectively.
In the switch 100, when an operable portion 102a in the tip side of the knob 102 is operated in a circumferential direction around the rotational shaft X1, the cams 105, 106 are operated by the operable elements 103, 104 to rotate around the rotational shaft X2.
For example, when the operable portion 102a of the knob 102 is operated in a pulling-up direction (refer to a sign A in FIG. 8C), the one switching element 108 switches on by the cam 106. In addition, when the operable portion 102a of the knob 102 is operated in a pushing-down direction (refer to a sign B in FIG. 8B), the other switching element 107 switches on by the cam 105.
Accordingly the switch 100 is configured such that the operating direction of the knob 102 is specified based upon which of the switching elements 107, 108 are switched on.
As described above, the switch 100 according to Patent Document 1 requires the switching element for detecting the operation of the knob 102.
Here, the switch element is provided with a two-line circuit for detecting an on/off operation of the switch from a point of view of a fail-safe. Therefore the switching element is relatively expensive, and the switch provided with this switching element is higher in cost percent of the switching element in manufacturing costs.
Therefore it is required to be able to specify the operation of the knob with a lower priced configuration.
The present invention is made in view of the aforementioned problems, and has an object of providing a switch that can specify an operation of a knob at lower cost.